1. Technical Field of the Invention
The present invention relates to technology for processing a sound signal.
2. Description of the Related Art
Japanese Patent Application Publication No. 2011-158674 discloses technology using a display device for displaying intensity distribution of a sound signal on a frequency-localization plane on which a frequency domain and a localization domain are set. According to Japanese Patent Application Publication No. 2011-158674, a sound component of a sound signal, which stays in a particular region (referred to as ‘target region’ hereinafter) set on the frequency-localization plane by a user, is extracted. Accordingly, it is possible to extract a sound component (e.g. sound of a specific musical instrument) included in a specific band, generated from a sound source located in a specific direction.
However, a sound signal may include a reverberation component. A localization estimated through analysis of a sound signal for a sound component (referred to as ‘initial sound component’ hereinafter) immediately after the sound signal is generated from a sound source (before the sound signal reverberates) may be different from a localization with respect to a reverberation component obtained when the initial sound component is reflected and diffused in an acoustic space. For example, even when the initial sound component is localized outside a target region, the reverberation component may be localized within the target region.
Accordingly, the technology of Japanese Patent Application Publication No. 2011-158674, which simply extracts a sound component corresponding to the target region, may inappropriately extract a reverberation component corresponding to the target region, which is derived from a sound source located outside the target region, along with the sound component generated from a sound source within the target region. Similarly, when the initial sound component is localized within the target region, its reverberation component may be localized outside the target region. Accordingly, when the sound component corresponding to the target region is suppressed according to the technology of Japanese Patent Application Publication No. 2011-158674, the reverberation component outside the target region may be inappropriately maintained without being suppressed together with a sound component from the sound source located outside the target region, and thus a listener perceives the reverberation component as being emphasized. As described above, the technology of Japanese Patent Application Publication No. 2011-158674 has a problem that a sound component of a sound source located in a specific direction is difficult to separate (emphasize or suppress) with accuracy.